Small gastrointestinal stromal tumor of the stomach showing rapid growth and early metastasis to the liver.

A 65-year-old man received upper gastrointestinal endoscopy. At that time, no abnormalities were identified in the stomach except for a submucosal tumor approximately 1 cm in maximal diameter at the gastric cardia. Two months later, he developed tarry stools and anemia. Colonoscopy revealed no abnormal findings in the colon or terminal ileum. Upper gastrointestinal endoscopy was re-evaluated in our hospital. Macroscopically, the previously detected submucosal tumor had grown to 3.0 cm in maximal diameter and the tumor was exposed by extensive ulceration. Biopsy specimens of the lesion indicated KIT-positive gastrointestinal stromal tumor (GIST) with a probability of high risk. Total gastrectomy was carried out and the resected GIST was found to comprise spindle-shaped tumor cells with 23 mitoses in 10 high-power fields. Mutation of the c-kit gene was studied using the surgical specimens, and deletion of five amino acids from codons 554-558 in exon 11 was detected. Liver metastasis was found 6 months postoperatively, and molecular target therapy was carried out. However, the patient died 2 years after the finding of liver metastasis.